An automatic colony counter is an important laboratory instrument widely used in microbiology, food testing, pharmaceutical analysis, environmental monitoring, and biological research. Compared with traditional manual counting methods, automatic colony counters provide faster analysis, higher accuracy, and reduced operator workload. However, correct operation is essential to ensure reliable counting results and extend the service life of the instrument. The following steps introduce how to properly operate an automatic colony counter.

1. Preparation Before Operation

Before using the automatic colony counter, the operator should first check the working environment and instrument condition. The instrument should be placed on a stable, clean, and dry laboratory bench away from strong vibration, excessive humidity, and direct sunlight. Check whether the power supply is stable and whether the instrument accessories, such as the counting plate, camera system, lighting source, and software connection, are functioning normally.

Before counting, prepare the microbial culture plates according to standard laboratory procedures. The surface of the culture medium should be free from excessive condensation, cracks, or contamination, as these factors may affect image recognition accuracy. Select appropriate counting parameters according to colony size, color, and growth characteristics.

2. Correct Placement of Culture Plates

When placing the Petri dish into the automatic colony counter, ensure that the plate is positioned correctly in the detection area. The lid of the Petri dish should be removed or adjusted according to the instrument design to avoid image interference. The plate should remain flat and centered under the camera.

For transparent plates or samples with low contrast, proper adjustment of the lighting conditions is necessary. The instrument’s illumination system should provide uniform brightness so that colonies can be clearly distinguished from the background. Incorrect placement or uneven lighting may cause missed counting or false counting.

3. Setting Counting Parameters and Starting Analysis

After placing the sample, open the instrument software and select the appropriate counting mode. Modern automatic colony counters usually provide intelligent image recognition functions, allowing users to adjust parameters such as colony size range, sensitivity, threshold value, and counting area.

Before starting automatic counting, users should preview the captured image and verify whether colonies are clearly identified. If the system recognizes background particles or ignores small colonies, the parameters should be adjusted. After optimization, start the automatic counting process and allow the software to complete image analysis.

For critical experiments, the operator should compare automatic results with manual observations or reference standards to confirm accuracy.

4. Maintenance After Use

After completing the counting operation, remove the culture plate and clean the instrument surface. The counting platform, optical window, and sample area should be wiped regularly with appropriate disinfectants to prevent microbial contamination.

Avoid touching the camera lens or optical components directly. Dust accumulation on optical parts may reduce image quality and affect counting accuracy. Regular calibration, software updates, and professional maintenance should also be performed according to the manufacturer’s recommendations.

Conclusion

Proper operation of an automatic colony counter includes careful preparation, correct sample placement, accurate parameter adjustment, and regular maintenance. Following standardized operating procedures can improve counting accuracy, reduce experimental errors, and ensure long-term stable performance. With correct use and maintenance, automatic colony counters can provide efficient and reliable support for microbiological analysis and laboratory research.